Humidification



oooooooeaco INVENTOR.

Jama W/Wifclze/l cooueanaoo o 4 Sheets-Sheet l HUMIDIFICATION J. w. MITCHELL Filed March 15,

MW ATTORNEY.

June 3Q, 1936. J. w. MITCHELL Z J HUMIDIFICATION Filed March 15, 1934 4 Sheets-Sheet 2 WWW M 4 5 g V Fig. 2

INVENTOR.

James W Michell A TT ORNE Y.

J. .W. MITCHELL HUMIDIFI CATION June 30, 1936.

Filed Maroh 15, 1934 v 4 Sheets-Sheet 5 w Q @m Ev 3 T I M llll m s .2 s S N INVENTOR.

B James WM'k/Id/ June 30, 1936. I J. w. MITCHELL HUMIDIFICATION Filed March 13, 1954 4 Sheets-Sheet 4 v 6 INVENTOR.

' James M Mkrfid/ ATTORNE Patented June 30, 1936 Ui'l'ED STATES PATENT OFIQE HUMIDIFICATION Application March 13, 1934, Serial No. 715,286

3 Claims.

This invention relates to a method for humidifying connected compartments. The invention is concerned primarily with the prevention of crystal formation in the buckets and bucket 5 compartments of machines for manufacturing artificial thread. The invention will be described in connection with the manufacture of viscose rayon, but the particular description does not limit the invention to the particular use.

In one process of manufacturing rayon by the viscose process the newly formed thread, still Wet with coagulating liquor, is gathered into the form of an annular cake in a centrifugal bucket. Excess liquid is thrown by the bucket into the compartment in which the bucket is located. At low bucket speeds no problem was caused by this discharge, but with high bucket speeds, and particularly in the spinning of fine filaments, enough liquid is evaporated to deposit crystals on the walls of the compartment and bucket and on the bottom of the bucket cover. Crystals from the cover drop into the bucket and damage the rayon, and the crystals on the bucket and in the compartment increase the power load considerably.

It has been proposed to minimize crystal formation in spinning bucket compartments by squirting a stream of water or steam against the side of the bucket. That method eliminates crystal growth on the outside of the bucket and 30 on the compartment walls, but is not sufiiciently effective in preventing crystal formation on the bottom of the bucket cover, is spotty in its action, and requires fluid at relatively high pressure within the bucket compartment.

An object of my invention is to prevent crystallization of coagulating bath liquor in a spinning bucket compartment. Another object of my invention is to humidify a bucket compartment or a series of compartments. A further object of my invention is to produce high quality artificial yarn in high speed buckets. Other objects of the invention Will be in part apparent and in part set forth in the description that follows.

The objects of my invention are accomplished generally speaking by passing air through water and into the compartment. More specifically the objects of the invention are accomplished by forcing air through a Water screen into an approximately circular bucket compartment.

In the drawings Figure 1 is a plan view partly in section of a portion of a thread manufacturing machine. Figure 2 is an end View partly in section on the line 2-2 of Figure 1. Figure 3 is an enlarged plan view of the bucket compartments partly in section showing the location of the humidifier. Figures 4 and 5 represent a screen. Figure 6 is an enlarged View of the humidifier showing the compartment walls partly in section on the line B -'6 of Figure 3.

Referring to the numerals of the drawings, I is the frame of the machine, represented in this instance to be wood but which is preferably made of corrosion-resistant metal; ii is a ventilating duct which serves to withdraw vapors from the spinning compartment and to largely prevent them from entering the spinning room; l2 is a waste liquor drain serving to carry the liquids from the bucket compartment to a recovery system or to the' sewer, as the case may be. Duct l I and drain I 2 extend the length of the machine, which may have as many as fifty positions. 2 are spinning bucket compartments, illustrated as circular in form; 2! are ducts, forming a part of the compartment, which connect the compartments with the ventilating duct; 22 is a cover for an individual bucket compartment; 22! is a hole in the bucket cover through which thread can be admitted to the bucket through a traversing funnel not shown; 3 is the top of a bucket driving mechanism; 3! is a centrifugal bucket mounted on the spindle 32 projecting from the driving mechanism 3; 4 is an air duct connecting adjacent compartments. This duct is preferably removable in order to facilitate repairs to bucket compartments, but it can be made integral with 1 the compartments if it is desired. M are lips on the duct projecting into adjacent compartments; 42 is a water pipe extending lengthwise of the machine and preferably passing through the base of each bucket compartment, although any other location within or outside of the compartment is satisfactory; 43 is a tank in the upper part of the air duct between compartments; 44 is a pipe connecting the water supply pipe 42 with tank 43; MI is a valve by which the water supply to individual tanks may be regulated; 45 are openings in the spinning bucket compartment walls coinciding substantially with the open ends of duct 4; 46 is a screen extending across the duct 4 directly beneath, and in connection with, the tank.

The operation of my system is as follows: The bucket is rotated at high speed and thread is admitted thereto through a traversing funnel. The rotation of the bucket forces air from the compartment into the ventilating duct and through the air passage into the next compartment. Water is turned on, so as to slowly flow along the sloping bottom of tank 43 and onto the screen. The air forced from the one compartment is loaded with moisture when it passes through the wet screen into the other compartment, and prevents the formation of crystals in the compartment and within the bucket.

Some advantages of this invention can be obtained by the use of a non-circular compartment, but a round or volute compartment acts much more efficiently than a rectangular compartment, enables the humidification apparatus to be placed between compartments, and is preferred.

The air outlet to the ventilation duct should be of a size which will permit air to be forced by the rotating bucket through the water screen into the necessary compartment. A passage too large will tend to prevent proper circulation through the water screen, and one toosmall will result in undesirable air turbulence within the receiving compartment. The permeability of the screen and size of the ducts should be regulated to prevent the setting up of strong air currents within the bucket compartments. The size of the screen and the amount of water flowed thereover should be regulated to secure the degree of humidification desired in the particular operation.

The water screen may be made of metal, such as lead, nickel, or aluminum; of artificial resin, as for example a phenol-formaldehyde resin; of rubberyor of cloth. The screen may be a perforated plate of any suitable material such as those above named; it may be a screen made of any suitable material; or it may be a fabric (such as a woven woolen sheet) when the nature of the material admits.

The water supply pipe 52 is under only suflicient head to insure a slight flow of water over each of the screens. Two or three pounds pressure is sufficient to attain perfectly satisfactory operation under normal conditions and even under unusual conditions pressures of no more than six or eight pounds per square inch are needed. This compares most favorably with systems of crystal prevention which involve spraying the bucket with a stream of water. In such systems a pressure in the neighborhood of thirty or forty pounds per square inch is required.

An advantage of this invention is that a compartment may be filled with saturate-d air without bringing a liquid into it. Bucket spinning machines equipped with this humidification system have been operated continuously for several Weeks without crystal formation, which compares favorably with machines not so equipped, which required cleaning by hand every few days. Crystals do not form on bucket covers, yarn is not damaged by crystals, and a better product results. By using low pressure water and eliminating the nozzles by which water is delivered under high pressure, mechanical simplification is secured and difficulties are eliminated. For instance, if a bucket should fly off the spindle or burst and break one of the water tubes, the low pressure water of our system will quietly flow out of the compartment into the waste trough, whereas if jets are used with accompanying high water pressure, the breaking of a pipe would damage equipment and make any contacted rayon unfit for use. Other advantages will be apparent.

While in the foregoing description, I have repeatedly referred to water as the humidifying agent, it is to be understood that other liquids and aqueous solutions may be used to good advantage. For example, I may use dilute sulfuric acid or a liquid such as is normally used as a coagulating bath in the spinning of viscose threads which makes it economically possible to recover the bath whereas, when water alone is used, the liquid drained from the compartments contains so little of the bath ingredients that recovery is not feasible.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. An apparatus for the manufacture of artificial thread which comprises bucket compartments connected by an air duct, centrifugal buckets within the compartments, a screen for obstructing the duct, and a water supply tank thereabove connected to said screen whereby water may be flowed over the screen.

2. An apparatus for the manufacture of artificial thread which comprises bucket compartments connected by an air duct, centrifugal buckets within the compartment, a screen for obstructing the duct, and means whereby water may be flowed over the screen.

3. The method of preventing the formation of crystals in a plurality of adjoining compartments of a bucket spinning machine, comprising with-drawing air from one compartment, humidifying the air, then introducing it into the next succeeding compartment.

JAMES W. MITCHELL. 

